Why use Apache Web Server in front of Glassfish or Tomcat?

Question

Is it good idea to use Apache Webserver in front of GF or Tomcat? Does it improve the performance/security?

Or there is not any reason to use Apache Web Server with

Answer 1

One reason to place Apache in front of Tomcat would be for load balancing.
Requests hit the Apache server in front and are distributed to backend Tomcat containers depending on load and availability.
The clients know of only one IP (Apache) but the requests are distributed over multiple containers.
So this is in the case you deploy a kind of distributed web application and you need it robust.
If your question is about a simple web application then see dbyrne answer